Most professionals think they have to change jobs every three years to get ahead. But you really don’t have to move to a new job or company to advance your career. Chances are, your current job offers challenges and opportunities you haven’t yet tapped. By taking on new assignments in your current position, you can expand your skill set and develop your leadership capabilities—and thus your marketability—without spending all that time and effort job-hunting.

The key to making progress in the workplace and in one’s career is to identify and take on developmental assignments. These are roles and activities that provide opportunities to learn new skills, expand your knowledge base, try new behaviors and improve on weaknesses. Because they usually involve an element of challenge or risk, they stretch you out of your comfort zone. A developmental assignment might lead you to work that is broader in scope than what you are used to, such as a project involving more people or coordinating with groups across the organization.

Developmental assignments can also come from the experience of starting something new, such as a new project or a new product line or championing a change, such as adopting a new technology or restructuring the workflow in your business unit. Taking on a "high stakes" role—one with a tight deadline, pressure from superiors, high visibility and responsibility for critical decisions, such as managing a big technology upgrade—will also take you out of your comfort zone and drive significant learning.

Here are some tips for identifying the developmental assignments that are right for you, for discussing these opportunities with your supervisor and for managing your new workload.

Find the right challenge. Before you jump into a new role or task, clarify what you are trying to learn. Ask yourself what skills, behaviors or actions you need to develop to be more effective. What do you need to learn for future assignments and opportunities? What are your strengths and weaknesses?

For each area you want to improve, brainstorm different ways you could learn and practice new skills or behaviors. If, for example, you want to improve your people skills, you can create an endless stream of developmental assignments by learning new ways to deal with people, face and resolve conflict, and coach employees. Serving as an IT liaison to the business is a great way to improve your people skills as is working with people from different cultures, races or ethnic backgrounds.

Look for opportunities to reshape your current job. There are a number of ways to go about doing this. You could trade tasks with a coworker or volunteer for a task that would normally go to a more experienced person. For example, if you’re a programmer, you could take on more project management responsibilities.

You can also ask your boss if she’ll delegate one of her responsibilities to you. If you want to learn more about finance and managing a budget, you could ask her if she’ll let you track expenses for a quarter. Or, if you want to take on the challenge of managing a high-visibility client account, ask your boss or another more senior colleague who has a number of these accounts to delegate one to you.

You can also reshape your job on your own. Re-examine responsibilities that are already a legitimate part of your job but haven’t been a priority. If coaching and developing your subordinates is a neglected role, then consider how to give them guidance and support. Or focus your coaching on that one person, who—with just a little more polishing—could turn out to be a star performer. The key is to do something you haven’t done before and learn what it takes to do it well.

Consider temporary assignments outside your job description or department. What new projects need an additional team member? Is there a task force that could benefit from your functional expertise and, at the same time, give you a broader perspective on the business? Are there annual events you’d like to plan that might help you improve your project management skills? Would a temporary assignment in another department broaden your knowledge of the business?

Manage the boss. If you have a boss who’s open and interested in your development, find a time to talk to her about why you want to take on new challenges. Be clear about the skills or behaviors you want to learn or improve. Suggest several assignments that interest you and ask her for other ideas. She may have specific activities or goals she needs your help achieving. Together, consider which assignments have the most promise and are mutually beneficial, and leave the discussion with a game plan for your developmental assignment. This game plan should specify what the assignment is, its time frame, the skills and behaviors you will practice, what you will gain from it, as well as the resources and support you will need to maximize your learning.

Having an involved and supportive manager is a great benefit, but if you’re uncomfortable bringing her in on your developmental plan, you have several options. First, you can step up to challenges that don’t require approval from the boss, such as improving the way you perform a current responsibility. You can also add a responsibility that nobody in your group currently owns but should. For example, if no one is paying attention to process improvements, managing shared resources or building effective connections with other groups, you could take on one of those tasks. You might also find a colleague, mentor or advocate in another area of the organization to help identify good opportunities for career development and suggest to your boss that you would be a good candidate to take advantage of those opportunities.

You can also circumvent your boss by choosing challenging assignments in your life away from work. You’ll find plenty of responsibilities in nonprofit, religious, social and professional organizations; schools; sport teams and family life that translate to valuable professional experience. For example, if weak presentation skills are limiting your potential at work, join a Toastmasters club, sign up to be a lay reader at your place of worship or teach a continuing education class. If you need experience leading a visible, high-stakes project, chair a fund-raising event in your community or work on a political campaign.

Get real. Taking on new challenges can be exciting, but it also means adding more responsibilities, which can be daunting. When choosing a developmental assignment, be realistic. Remember, your goal is to weave in new experiences while you maintain your current role and commitments. These strategies will help you balance new assignments with your existing work:

Learn to work more efficiently. The pressure of added responsibility stimulates most people to learn how to accomplish more in the same amount of time. Look for opportunities to be more decisive, to let go of tasks that should be delegated to others, to work faster and to create better systems for monitoring and tracking work.

Plan short-term and long-term. You might be able to orchestrate some developmental assignments rather quickly. You might have to put others on hold as you wait for the right opportunity to emerge. You may get as much out of a small-scale, ongoing assignment (e.g., being a peer coach for new employees) or a short-term project (e.g., serving on a hiring committee) as you would from a larger commitment (e.g., joining a new R&D project).

Schedule—and protect—your time. This is easier if your assignment involves specific meeting times and clear deadlines, but block out time for other key activities that will help you make the most of your developmental assignment, such as study and practice, writing in a learning journal or meeting with a mentor.

Get support. Bring family, friends and coworkers in on your plans and progress. Ask for their feedback and encouragement, as well as for tangible help, such as taking your place at a meeting, cooking dinner or carpooling, that will give you more time to devote to your developmental assignment. But keep in mind that you’ll need to return these favors in the future when those who have helped you need your help in their own developmental assignments.

By taking on challenges with the goal of learning, you gain a broad portfolio of experiences that enhance your performance in your current job and prepare you for the next one, when you are finally and truly ready to seek it out.

Cynthia D. McCauley is author of Developmental Assignments: Creating Learning Experiences without Changing Jobs (CCL, 2006.) She is a senior fellow at the Center for Creative Leadership as well as its former vice president for leadership development. She has a PhD in industrial and organizational psychology from the University of Georgia.